Solvent-based, aliphatic, polyurethane top coat


The MARISEAL 420 is a pigmented, wear resistant, semirigid, color- and UV-stable, weather-stable, cold applied and cold curing, one component aliphatic polyurethane coating used as a top-coat for protection over exposed waterproofing coatings, subject to high wear conditions.

Cures by reaction with ground and air moisture over a unique moisture triggered chemical reaction.


  • Simple application (roller or airless spray)
  • One component
  • Resistant to constant, heavy abrasion and wear conditions.
  • UV stable
  • Color stable.
  • Gives a glossy and easy-to-clean surface
  • Does not show the chalking effect of aromatic polyurethane waterproofing coatings.
  • Resistant to water
  • Resistant to frost
  • Maintains its mechanical properties over a temperaturespanof-40C to +90C
  • The waterproofed surface can be walked on(domestic pedestrian traffic).


  • Waterproofing of Decks and Walkways
  • Waterproofing of public Pedestrian Traffic Areas
  • Waterproofing of Exposed Car Parking areas
  • Waterproofing of surfaces exposed to heavy wear conditions.

Used over the MARISEAL 250 or 260, on surfaces with high public pedestrian trafficking (e.g. Stadium tribunes) and on surfaces with light car traffic (e.g. Exposed car parking areas)


400-500 gr/m2 in two layers.
This coverage is based on practical application by roller onto a smooth surface in optimum conditions. Factors like surface porosity, temperature, humidity, application method and finish required can alter consumption.


The MARISEAL 420 is supplied in white, light grey and red. Other RAL colors may be supplied on demand.

Technical Data

PROPERTY RESULTS TEST METHOD Composition Pigmented Aliphatic moisture triggered
Polyurethane polymer. Solvent based Resistance to Water Pressure No Leak DIN EN 1928

Elongation at break >100% DIN EN ISO 527 Tensile strength >5 Ν/mm2 DIN EN ISO 527 Surface chalking after 2000h of accelerated aging
(DIN EN ISO 4892-3, 400 MJ/m2) No chalking observed. Chalking grade 0 DIN EN ISO 4628-6 Adhesion to the MARISEAL® 250 >2 N/mm 2 ASTMD 903 Hardness (Shore A Scale) 30 ASTMD 2240 (15”) UV accelerated ageing, in the presence of moisture >Passed – No significant changes EOTA TR-010 Hydrolysis (5% KOH, 7days cycle) No significant elastomeric change Inhouse Lab Service Temperature -40C to +90C Inhouse Lab Tack Free Time 1-4 hours Conditions: 20C, 50% RH Light Pedestrian Traffic Time 12 hours Conditions: 20C, 50% RH Final Curing time 7 days Conditions: 20C, 50% RH Chemical Properties Good resistance against acidic and alkali solutions (5%), detergents, seawater and oils.


Surface Preparation

Careful surface preparation is essential for optimum finish and durability.
The surface needs to be clean, dry and sound, free of any contamination, which may harmfully affect the adhesion of the membrane. Maximum moisture content should not exceed 5%. Substrate compressive strength should be at least 25MPa, cohesive bond strength at least 1.5MPa. New concrete structures need to dry for at least 28 days. Old, loose coatings, dirt, fats, oils, organic substances and dust need to be removed by a grinding machine. Possible surface irregularities need to be smoothened. Any loose surface pieces and grinding dust need to be thoroughly removed.
WARNING: Do not wash surface with water!

Waterproofing Membrane

See relevant MARIS POLYMERS product Technical Data Sheet. Make sure that the last layer is broadcasted with silica sand.


Stir MARISEAL 420 well before using.
Apply the MARISEAL 420 by roller or airless spray in one or two layers.
Allow 3-6 hours (not more than 36 hours) to cure, between the two layers.

ATTENTION: The MARISEAL 420 must always be used over MARISEAL 250 / 260, which was previously sprinkled with oven dry silica sand or corundum (corn size 0,1-0,3mm or 0,4-0,8mm) which creates an adhesion bridge. With the silica sand in the last layer of the MARISEAL 250 / 260, the surface also becomes harder and more resistant to wear conditions.

For best results, the temperature during application and cure should be between 5C and 35C. Low temperatures retardcurewhilehigh temperature speed up curing. High humidity may affect the final finish.

WARNING: The MARISEAL 420 is slippery when wet. In order to avoid slipperiness during wet days, sprinkle suitable aggregates onto the still wet coating to create an anti-slip surface. Please contact our R+D Dept. for more details. WARNING: If on the surface where the MARISEAL system is applied, there are areas with ponding water, they should be cleaned on regular basis to avoid biological and microbial attack.


MARISEAL 420 is supplied in 20 kg, 10 kg and 5 kg metal pails. Pails should be stored in dry and cool rooms for up to9months.Protect the material against moisture and direct sunlight. Storage temperature: 5-30C. Products should remain in their original, unopened containers, bearing the manufacturers name, product designation, batch number and application precaution labels.

Safety measures

MARISEAL 420 contains isocyanates. See information supplied by the manufacturer. Please study the Safety Datasheet. PROFESSIONAL USE ONLY.

Mariseal 420



Mariseal 420 is a pigmented, wear-resistant, semi-rigid, colour and UV-stable, weather-stable, cold-applied and cold-curing, one component aliphatic polyurethane coating used as a top coat for protection of exposed waterproofing coatings subject to high wear conditions.

5L – 19cm x 19cm x 20cm
20L – 28cm x 28cm x 36cm

400-500gm per sq m in two coats

No of Coats:
2 coat application

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